As the level of climbing and mountaineering has advanced, climbers have developed a need for better portable cots for sleeping and shelter during multi-day ascents of vertical cliffs and rock faces. A portable cot that can be stowed in a climber's equipment bag and assembled during mid-climb allows a climber to rest and obtain shelter from inclement weather as required. These versatile ledges can be used to weather a passing storm, provide a bed during the night of a multi-day climb, and may even be used as a base camp for expeditions that can last 30 days or more. Climbers rely on the hanging cots for relief and respite, and there is naturally a preference for hanging cots that are safe, lightweight, easily carried by the climber, and are quickly assembled and dismantled. Also, cots with many separated small components that can be lost or fall pose significant problems, so climbers would be better served if the cots have a limited number of separate elements to assembly. It is also preferable to have a cot that offers a maximum usable (living) surface area to weight ratio.
In alpine climates and other mountain areas, it is common for storms to arrive in with very little notice, a situation that can pose substantial risk to a climber. In this situation it is essential that a shelter with a cot adjoining a vertical rock face be assembled quickly. If the climber is alone or separated from a group—thus requiring individual assembly—the need for quick and easy assembly is even more imperative. Solo ascents of routes requiring a ledge have become a more regular occurrence. Further, for routes where a team of climbers live on a rock face for weeks at a time, it is important that they have a safe and comfortable base camp on the face of the rock to recover each night and to wait out storms that can sometimes last consecutive days. In all climbing events it is important for comfort and energy conservation that the ledge be as light weight as possible. The success of these expeditions is greatly affected by the energy and morale of the team, and these are greatly affected by how well they can recover each night.
A typical prior art portable ledge comprises a collapsible rectangular framework of connectable aluminum tubing with a cloth bed that attaches around the frame. The framework is suspended by a series of straps that are attached by one end to each corner and possibly the middle of the long sides of the rectangle. The other ends of these straps are sewn together at a central point above the ledge and approximately at the center. This central hanging point is secured to an anchor in the rock, forming a tent like structure hanging against the wall. These typically come with an optional “fly,” a protective covering or tarp that extends from the anchor point over the ledge and straps to protect the climber from the weather.
These prior art ledges can be difficult to both assemble and dismantle. They consist of up to eight or more separate tubes and eight or more joints that each must be fitted together every time the ledge is to be assembled. The climber must locate appropriate complimentary components and construct the structure one piece at a time. If a connecting component should be dropped or lost, the results could be dire. Once the tubes are assembled into a framework, the bed must be secured and tensioned by the climber. This can be hazardous when a storm unexpectedly rolls in and a shelter must be quickly assembled. Likewise, dismantling the ledge can be as difficult as assembling it. Gravitational forces on the framework due to the weight of the cot can cause the tubes and joints to cam or rub together, making it difficult to retract the tubes from their fittings. Cold (or hot) weather can also exacerbate this problem and make disassembly awkward and difficult. This can delay the start of a day's climb and cause a frustrating situation before a day's climb has even begun.
Because of the constant push to reduce the weight of all gear carried, prior art ledges are sized to fit the average climber's shoulder width and sleeping length. Although this is usually acceptable during the period when a climber is sleeping, should it be necessary to put the protective covering (or “fly”) down and wait out a storm, the prior art cots provide an uncomfortably confined living space—especially when used for multiple days in a row. These living conditions can sap a climber's enthusiasm and affect the success of the team on an expedition.
Another significant drawback to the prior art cots results from the system of joints. When the ledge is fully assembled it is possible for the tubes to rotate and/or slide within the joints, resulting in a departure from the preferred planar configuration. This condition may cause a slight warping of the cot (referred to as “potato chipping”). If this occurs while the climber is sleeping, the resulting discovery of this condition from a sound sleep at perilous heights can be quite unnerving. The safety of a ledge with this tendency is very questionable. The consequence is that many climbers have spent sleepless nights because their ledge had “potato chipped,” and this condition has been known to have thrown a climber from his ledge.
Examples of prior art ledges include U.S. Pat. No. 5,860,175 to Saiki entitled Self Unfolding Portable Hanging Cot. Saiki teaches a rectangular cot using a system of pivots and hinges that unfolds into an operative position. Saiki's apparatus is excessively heavy and doesn't solve the problem of a confined living space. U.S. Pat. No. 5,898,960 to Hill, entitled Portable Ledge Apparatus And Method, discloses four support arms that fold into place from a central retainer member. These ledges fail to overcome the shortcomings of the prior art, and thus there remains a void in the prior art for a portable ledge that is lightweight, that can be easily assembled and dismantled by a single user, that offers sufficient space for living on the face of a cliff, and that is safe and reliable in all conditions.